1. Field
Example embodiments relate to methods of fabricating a single crystal silicon rod and a single crystal silicon rod structure. Other example embodiments relate to methods of fabricating a single crystal silicon rod having relatively no defects by forming and recrystallizing a rod in a portion of a silicon layer and a single crystal silicon rod structure.
2. Description of the Related Art
When amorphous silicon is cooled or solidified after being melted during the supply of energy using a laser, crystallization of silicon extracted as a crystal may be performed. According to the crystal growth of silicon grains, when a direction in which the silicon crystal grows is uniform, a single crystal may be obtained. When a plurality of crystals grows simultaneously at random, a polycrystal may be obtained.
When an amorphous silicon thin film is crystallized and used as an active layer of a thin film transistor or a channel region of a semiconductor device, the size of the silicon grain may increase in order to decrease the number of grain boundaries that interrupt the movement of carriers so that the characteristics of the device may improve.
When the amorphous silicon is applied to the device, mobility of electrical charges may be relatively low so that realization of a high speed operation may be difficult. Thus, the amorphous silicon for the device with a high resolution display may be difficult to use. To solve this problem, a thin film transistor may be formed after forming a polycrystalline silicon by crystallizing the amorphous silicon. The channel region of the thin film transistor may be formed of polycrystalline silicon. The charge mobility of the polycrystalline silicon may be about 100 times faster or more than that of amorphous silicon.
A method of fabricating polycrystalline silicon having a relatively large grain size may include a method of crystallizing an amorphous silicon thin film deposited on a substrate, for example, an excimer laser annealing (ELA) method and a solid phase crystallization (SPC) method. A metal induced lateral crystallization (MILC) method, which is an improved version of the ELA method or a continuous grain solidification (CGS) method, may be widely used. Also, a micro-Czochralski process may be used in which a hole is formed in an insulation layer and the amorphous silicon filling the hole is crystallized using a laser. All these methods employ crystallizing an amorphous silicon thin film into a polycrystalline silicon thin film.
However, a relatively large number of grain boundaries may still remain in the polycrystalline silicon thin film so that the flow of charges may be interrupted. Thus, to obtain improved electrical characteristics, the entire region, where a channel of a thin film transistor or a semiconductor device is formed, may be formed of a single crystal silicon.